Paper stacker

ABSTRACT

A paper stacker suitable for feeding prefolded paper, provided on both edges with a perforation track, to a paper collecting table. A number of paper guides open above a table arranged to be resilient with respect to the paper guide. The table has a raised portion which extends over the entire length of the table, between and substantially parallel to the perforation tracks of the folded paper.

United States Patent Dec. 23, 1975 Buisman PAPER STACKER 2,906,527 9/1959 Blain 270/61 F I 3,255,662 6/]966 Call 270/61 F X [75] lnvemo" Anflmn'us Theodmus Mam 3,342,390 9/1967 Winterbottom et a1, 270/79 x 3015mm Beekbetgem Netherlands 3.464.610 9/1969 Koning .s 270/79 x [73] Assignee: U.S. Philips Corporation, New

York Primary ExaminerLawrence Charles [22] Filed: Oct. 18, 1974 Attorney, Agent, or FirmFrank R. Trifari; David R. 21 Appl. No.: 516,0(13

Related US. Application Data [63] Continuation of Ser. No 347,805, April 4, 1973. [57] ABSTRACT abandoned.

A paper stacker suitable for feeding prefolded paper, [30] Forelgn Application Priority Data provided on both edges with a perforation track, to a Apr. 15, 1972 Netherlands..................... 72051 13 p p collecting l A n m r f p p g i s p n above a table arranged to be resilient with respect to [52] US. Cl. 270/61 F; 270/73 the paper guide. The table has a raised portion which [51] Int. Cl! B6511 45/00 nds r th n ir ng of t l between [58] Field of Search 270/6] F, 73 79 and substantially parallel to the perforation tracks of the folded paper. [56 References Cited UNITED STATES PATENTS 2 Claims, 4 Drawing Figures 940,933 11/1909 Klein 270/73 x US. Patent Dec. 23, 1975 Sheet 2 of2 3,927,874

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PAPER STACKER This is a continuation of application Ser. No. 347,805, filed April 4, 1973, and now abandoned The invention relates to a paper stacker which is suitable for feeding pre-folded paper, provided on both edges with a perforation track, to a paper collecting table and which comprises a paper guide which opens centrally above the table and along which the paper is fed during operation.

Paper stackers of the kind set forth are used in printing machines which print, for example, data originating from a computer. Very high paper speeds are then feasible, which makes it difiicult to collect the prefolded paper neatly folded on a table or in a bin again. If a disturbance occurs, the paper will be very chaotically deposited on or besides the table. This necessitates substantial supervision.

The object of the invention is to provide a paper stacker which has a very simple construction and which is very reliable in operation.

The paper stacker according to the invention has a paper collecting table arranged to be resilient with respect to the paper guide and displaceable along guides, the table furthermore having a raised portion which extends along the entire length of the table, between and substantially parallel to the side walls which extend transverse to the paper guide.

Because the table is arranged to be resilient, it will be lowered under the weight of the paper, so that substantially the same distance is always maintained between the top of the paper stack and the paper guide. This aids neat folding of the paper on the table. Particularly in the case of high speeds, the folding edges of the paper strike the paper stack at substantially right angles, after which it comes to rest while the sharp fold shifts over the paper stack. In the case of paper which is provided with a perforation track on its edges, this is difiicult in that, because of the perforations, the paper is slightly thicker at its edges. Consequently, the paper stack sags slightly in the middle and the sharp fold of the arriving paper bears exactly where the perforation tracks are provided.

Because the paper is not smooth at this area, the sharp fold cannot readily slide. This leads to irregular stacking.

This drawback is eliminated in the device according to the invention in that the table is provided with a raised portion which extends along the entire length of the table and which is parallel to the side edges of the table where the perforation tracks extend. The paper stack will thus no longer sag in the middle, so that the arriving paper will be neatly stacked.

So as to eliminate the problems appearing in the case of high and irregular paper speeds, one or more rings are suspended above the table on both sides of the paper guide in a further embodiment of the device according to the invention. The effect of these rings will be explained in detail in the description given with reference to the Figures.

FIGS. 1 and 2 diagrammatically show, by way of example and not to scale, a paper stacker in front and side views respectively.

FIGS. 3 and 4 diagrammatically show how the paper behaves at a medium and at a very high speed, respectively.

The reference numeral 1 in FIGS. 1 and 2 denotes a base plate. Arranged on this base plate 1 are four hollow columns 2. A table 3 is guided in the hollow columns 2 via guides 4. The guides 4 are suspended from springs 5, the tension of which can be adjusted by means of adjusting screws 6.

Also connected to the columns 2 is a paper guide 7. Arranged on both sides of and below the paper guide 7 is a rod 8 on which three plastic rings 9 hang freely.

The table 3 is provided with a raised portion 10 which extends between and substantially parallel to the short sides of the table, i.e. transverse to the paper guide.

The operation of this device is as follows.

When the paper is fed at a low speed, it follows as denoted in FIG. 2 by a broken line. That is to say, from the paper guide 7 the paper is transported between the rings 9 to the corner in which the fold is situated, after which the paper is lowered onto the paper stack already present. The table 3 is lowered under the weight of the paper so that the distance between the upper side of the paper stack and the opening of the paper guide remains constant.

In the case of a higher paper speed, the paper behaves as shown in FIG. 3. Due to its higher speed, the paper now immediately strikes the paper stack so that the paper rests on the paper stack with a sharp folding edge. The arc in the paper, tending to be formed due to the air present therebelow, is held back as if it where by the left-hand rings 9 which, consequently exert a force on the paper. This force, in conjunction with the force delivered by the weight of the paper arc, causes a shift of the sharp edge to the right. This shift can readily take place because according to the invention the table is provided with a raised portion 10 which ensures that the perforated edges can never project above the remainder of the paper. Consequently, these edges will not hamper the shifting so that the paper will also be properly folded at this speed.

In the case of a very high speed, the paper behaves as diagrammatically shown in FIG. 4. The paper now arrives so fast that it does not have time to pass between the rings 9. It now strikes the right-hand ring 9 and the next page is folded against the page held by the ring 9. After a number of pages have been folded against the ring, in practice usually after three pages, their weight is such that the rings 9 are forced to the side and the relevant pages are neatly lowered onto the already formed paper stack. The process is then repeated.

It will be obvious from the foregoing that the invention provides a device in which the paper is stacked without disturbances at any speed. Moreover, the construction of this device is very simple and inexpensive and requires little or no maintenance.

What is claimed is:

l. A paper stacker for feeding prefolded paper having a perforation track on both sides thereof to a paper collecting table comprising a guide which opens above the table and which feeds the paper to fold on the table during operation, means resiliently supporting and guiding said table so as to be movable with respect to said guide, said table having side portions parallel to the perforation tracks of the folded paper and a raised portion extending along the entire length of said table receiving said papers, said raised portion being located between and having a longitudinal axis substantially parallel to said side portions.

2. A paper stacker as claimed in claim 1 comprising in addition at least one ring hanging freely from fixed means located above said table on each side of said paper guide for exerting forces on the paper.

l l= =l 

1. A paper stacker for feeding prefolded paper having a perforation track on both sides thereof to a paper collecting table comprising a guide which opens above the table and which feeds the paper to fold on the table during operation, means resiliently supporting and guiding said table so as to be movable with respect to said guide, said table having side portions parallel to the perforation tracks of the folded paper and a raised portion extending along the entire length of said table receiving said papers, said raised portion being located between and having a longitudinal axis substantially parallel to said side portions.
 2. A paper stacker as claimed in claim 1 comprising in addition at least one ring hanging freely from fixed means located above said table on each side of said paper guide for exerting forces on the paper. 